A failure of air traffic radar in Brazil caused controllers to turn back some international flights early Saturday.

Other flights were ordered to make unscheduled landings at other airports. The problem occurred at the air traffic control center at Manaus in northern Brazil. Flights were allowed to resume after the problem was fixed.

The outage came just hours after Brazilian President Luiz Inacio Lula da Silva promised a thorough investigation of Tuesday's airliner crash at Sao Paulo that killed at least 189 people.

A TAM airlines Airbus 320 ran off the end of the runway, hit a building and burned. Everyone on the plane and several people on the ground were killed.

On Saturday, officials said they had located the plane's cockpit voice recorder. The device was sent to Washington for analysis.

Brazilian authorities had already sent to Washington what they thought were the airliner's two "black boxes." But one turned out to be a tape recorder not related to the flight data system.